272 SILUEID^E. 



maxillary. Gill-rakers moderately long, 9 to 10 on anterior arch. 

 Dorsal 140-150, separated from occipital process by a space equal to 

 or greater than length of head. Anal 125-130. Dorsal and anal 

 completely united with caudal. Pectoral absent or reduced to a minute 

 rudiment without spine. No trace of ventral. Vent at the anterior 

 fourth of the total length. Uniform dark brown or black. 



Total length 310 millim. 



Congo and Angola. 



1. Type. Ambriz, Angola. J- J- Monteiro, Esq. (0.). 



2. Ad. Siala Ntoto, Mayombe. Major Cabra (C). 

 3-5. Hgr. Lower Congo. M. F. Hens (C). 



6. Yg. Monsembe, Upp. Congo. Rev. J. H. Weeks (P.). 



7. Skel. „ „ » 



8. Ad. New Antwerp, Upp. Congo. Capt. Wilverth (C). 



9. Ad. Stanley Falls, „ Rev. W. H. Bentley (C). 



10. Hgr. Banzyville, Ubanghi. Capt. Royaux (C). 



11. Ad. Congo? 



6. HETEROBRANCHUS. 

 Geoffr. Descr. Egypte, Poiss. (1809), part. ; Giinth. Cat, Fish. v. p. 21 (1864); 

 Bouleng. Poiss. Bass. Congo, p. 265 (1901), Fish. Nile, p. 300 (1907), and 

 Proc. Zool. Soc. 1907, p. 1094. 



Distinguished from Clarias by the division of the dorsal fin into two 

 parts, the posterior adipose and supported by the prolongations of the 

 neural spines. 



Vertebrae 60-65. 



Three species from Africa, and one from the Malay Archipelago. 



Synopsis of the Species. 



D. 38-45 ; adipose fin j-| length of rayed 



dorsal ; pectoral not more than ^ length o£ 



head ; 20-30 gill-rakers on anterior arch. 1. IT. hidorsal/s, I. Geoffr., p. 273. 

 D. 29-34 ; adipose fin as long as or a little 



shorter than rayed dorsal ; pectoral not 



more than \ length of head ; 20-30 gill- 

 rakers on anterior arch 2. II. Iniiijifilh, C. & V., p. 274. 



D. 30-32 ; adipose fin as long as or a little 



shorter than rayed dorsal ; pectoral -J length 



of head ; 18-20 gill-rakers on anterior 



arch 3. //. isopterus, Blkr., p. 276. 



